Density of Oil
Density of Oil

What is oil density? Oil density is a crucial property not only in lubricants but in all fluids. For instance, as the density of a lubricant increases, the fluid becomes thicker. This leads to an […]


It is said that a contact operates under “starvation conditions” when an increase of oil supply at the contact would result in an increase of the film thickness at the contact. In other words, when […]

Viscosity Index Calculation
Viscosity Index

What is viscosity index? The viscosity index (VI) is an arbitrary, unitless measure of a fluid’s viscosity change relative to a temperature change. We can say that the it is the dimensionless number that shows how the […]

flame hardening
Flame Hardening

What is flame hardening? By putting the solid red-hot steel into water ( producing martensite), and tempering the quench-hardened steel at a moderate temperature, have been known and used for thousands of years. The extensively […]

spalling failure ring
Spalling Damage

Bearing Failure Modes Bearing damage, and ultimately, failure, can be caused by a variety of conditions, including improper mounting, poor lubrication, and overloading, to name a few. The mode of damage — what actually happened […]


What is lapping? Lapping is a type of finishing process which is carried out with the help of loose abrasives. In this finishing process, surface smoothening is achieved by the abrasive grains which are supported […]

Francesco Melzi - Portrait of Leonardo
Tribology History

Tribology Milestones Although the term tribology was only coined in 1966 by Peter Jost, humans have recognized the concept in some form for thousands of years. The earliest mention of tribology is actually in the […]